01 - Preheat oven to 300°F. Rub the chuck roast thoroughly with olive oil, then evenly coat with salt, pepper, smoked paprika, garlic powder, and onion powder on all sides.
02 - Heat a Dutch oven over medium-high heat. Sear the seasoned beef on all sides until deeply browned, approximately 4-5 minutes per side. Remove beef and set aside on a plate.
03 - In the same Dutch oven, add sliced onions and minced garlic. Sauté for 2-3 minutes, stirring occasionally, until onions are softened and fragrant.
04 - Pour in beef broth, barbecue sauce, Worcestershire sauce, brown sugar, and apple cider vinegar. Stir well to combine and bring the mixture to a gentle simmer.
05 - Return the seared beef to the pot, nestling it into the liquid. Cover tightly with the lid and transfer to the preheated oven. Braise for 4 hours, turning the beef once halfway through cooking, until meat is fork-tender and easily shreds.
06 - Remove the beef from the cooking liquid and transfer to a cutting board. Use two forks to shred the meat into bite-sized pieces. Skim excess fat from the braising liquid, then return the shredded beef to the pot and toss thoroughly to coat in the juices.
07 - Increase oven temperature to 350°F. Slice the slider buns in half horizontally and brush the cut sides lightly with melted butter. Arrange on a baking sheet and warm in the oven for 5 minutes until lightly toasted.
08 - Pile a generous portion of the juicy pulled beef onto the bottom half of each bun. Top with 1-2 pickle slices and crown with the bun tops. Serve immediately while warm.